﻿
<!DOCTYPE html>

<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>11、球体、旋转矩阵和鼠标事件</title>

    <script type="text/javascript" src="../js/Oak3D_v_0_5.js"></script>

    <script id="shader-fs" type="x-shader/x-fragment">

        precision mediump float;


        varying vec2 vTextureCoord;
        varying vec3 vLightWeighting;

        uniform sampler2D uSampler;

        void main(void) {
        vec4 textureColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
        gl_FragColor = vec4(textureColor.rgb * vLightWeighting, textureColor.a);
        }
    </script>

    <script id="shader-vs" type="x-shader/x-vertex">
        attribute vec3 aVertexPosition;
        attribute vec3 aVertexNormal;
        attribute vec2 aTextureCoord;

        uniform mat4 uMVMatrix;
        uniform mat4 uPMatrix;
        uniform mat4 uNMatrix;

        uniform vec3 uAmbientColor;

        uniform vec3 uLightingDirection;
        uniform vec3 uDirectionalColor;

        uniform bool uUseLighting;

        varying vec2 vTextureCoord;
        varying vec3 vLightWeighting;

        void main(void) {
        gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
        vTextureCoord = aTextureCoord;

        if (!uUseLighting) {
        vLightWeighting = vec3(1.0, 1.0, 1.0);
        } else {
        vec3 transformedNormal = (uNMatrix * vec4(aVertexNormal,1.0)).xyz;
        float directionalLightWeighting = max(dot(transformedNormal, uLightingDirection), 0.0);
        vLightWeighting = uAmbientColor + uDirectionalColor * directionalLightWeighting;
        }
        }
    </script>


    <script type="text/javascript">

        var gl;

        function initGL(canvas) {
            try {
                gl = canvas.getContext("experimental-webgl");
                gl.viewportWidth = canvas.width;
                gl.viewportHeight = canvas.height;
            } catch (e) {
            }
            if (!gl) {
                alert("Could not initialise WebGL, sorry :-(");
            }
        }


        function getShader(gl, id) {
            var shaderScript = document.getElementById(id);
            if (!shaderScript) {
                return null;
            }

            var str = "";
            var k = shaderScript.firstChild;
            while (k) {
                if (k.nodeType == 3) {
                    str += k.textContent;
                }
                k = k.nextSibling;
            }

            var shader;
            if (shaderScript.type == "x-shader/x-fragment") {
                shader = gl.createShader(gl.FRAGMENT_SHADER);
            } else if (shaderScript.type == "x-shader/x-vertex") {
                shader = gl.createShader(gl.VERTEX_SHADER);
            } else {
                return null;
            }

            gl.shaderSource(shader, str);
            gl.compileShader(shader);

            if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
                alert(gl.getShaderInfoLog(shader));
                return null;
            }

            return shader;
        }


        var shaderProgram;

        function initShaders() {
            var fragmentShader = getShader(gl, "shader-fs");
            var vertexShader = getShader(gl, "shader-vs");

            shaderProgram = gl.createProgram();
            gl.attachShader(shaderProgram, vertexShader);
            gl.attachShader(shaderProgram, fragmentShader);
            gl.linkProgram(shaderProgram);

            if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
                alert("Could not initialise shaders");
            }

            gl.useProgram(shaderProgram);

            shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
            gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);

            shaderProgram.textureCoordAttribute = gl.getAttribLocation(shaderProgram, "aTextureCoord");
            gl.enableVertexAttribArray(shaderProgram.textureCoordAttribute);

            shaderProgram.vertexNormalAttribute = gl.getAttribLocation(shaderProgram, "aVertexNormal");
            gl.enableVertexAttribArray(shaderProgram.vertexNormalAttribute);

            shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
            shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
            shaderProgram.nMatrixUniform = gl.getUniformLocation(shaderProgram, "uNMatrix");
            shaderProgram.samplerUniform = gl.getUniformLocation(shaderProgram, "uSampler");
            shaderProgram.useLightingUniform = gl.getUniformLocation(shaderProgram, "uUseLighting");
            shaderProgram.ambientColorUniform = gl.getUniformLocation(shaderProgram, "uAmbientColor");
            shaderProgram.lightingDirectionUniform = gl.getUniformLocation(shaderProgram, "uLightingDirection");
            shaderProgram.directionalColorUniform = gl.getUniformLocation(shaderProgram, "uDirectionalColor");
        }


        function handleLoadedTexture(texture) {
            gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
            gl.bindTexture(gl.TEXTURE_2D, texture);
            gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, texture.image);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
            gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
            gl.generateMipmap(gl.TEXTURE_2D);

            gl.bindTexture(gl.TEXTURE_2D, null);
        }


        var moonTexture;

        function initTexture() {
            moonTexture = gl.createTexture();
            moonTexture.image = new Image();
            moonTexture.image.onload = function () {
                handleLoadedTexture(moonTexture)
            }

            moonTexture.image.src = "../texture/moon.gif";
        }


        var mvMatrix;
        var mvMatrixStack = [];
        var pMatrix;

        function mvPushMatrix() {
            var copy = new okMat4();
            mvMatrix.clone(copy);
            mvMatrixStack.push(copy);
        }

        function mvPopMatrix() {
            if (mvMatrixStack.length == 0) {
                throw "Invalid popMatrix!";
            }
            mvMatrix = mvMatrixStack.pop();
        }


        function setMatrixUniforms() {
            gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, pMatrix.toArray());
            gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mvMatrix.toArray());

            var normalMatrix = mvMatrix.inverse().transpose();
            gl.uniformMatrix4fv(shaderProgram.nMatrixUniform, false, normalMatrix.toArray());
        }








        function degToRad(degrees) {
            return degrees * Math.PI / 180;
        }


        var mouseDown = false;
        var lastMouseX = null;
        var lastMouseY = null;

        var moonRotationMatrix = new okMat4();

        function handleMouseDown(event) {
            mouseDown = true;
            lastMouseX = event.clientX;
            lastMouseY = event.clientY;
        }


        function handleMouseUp(event) {
            mouseDown = false;
        }


        function handleMouseMove(event) {
            if (!mouseDown) {
                return;
            }
            var newX = event.clientX;
            var newY = event.clientY;

            var deltaX = newX - lastMouseX
            var newRotationMatrix = new okMat4();
            newRotationMatrix.rotY(OAK.SPACE_LOCAL, deltaX / 10, true);

            var deltaY = newY - lastMouseY;
            newRotationMatrix.rotX(OAK.SPACE_LOCAL, deltaY / 10, true);

            moonRotationMatrix = okMat4Mul(newRotationMatrix, moonRotationMatrix);

            lastMouseX = newX
            lastMouseY = newY;
        }



        var moonVertexPositionBuffer;
        var moonVertexNormalBuffer;
        var moonVertexTextureCoordBuffer;
        var moonVertexIndexBuffer;

        function initBuffers() {
            var latitudeBands = 30;
            var longitudeBands = 30;
            var radius = 2;

            var vertexPositionData = [];
            var normalData = [];
            var textureCoordData = [];
            for (var latNumber = 0; latNumber <= latitudeBands; latNumber++) {
                var theta = latNumber * Math.PI / latitudeBands;
                var sinTheta = Math.sin(theta);
                var cosTheta = Math.cos(theta);

                for (var longNumber = 0; longNumber <= longitudeBands; longNumber++) {
                    var phi = longNumber * 2 * Math.PI / longitudeBands;
                    var sinPhi = Math.sin(phi);
                    var cosPhi = Math.cos(phi);

                    var x = cosPhi * sinTheta;
                    var y = cosTheta;
                    var z = sinPhi * sinTheta;
                    var u = 1 - (longNumber / longitudeBands);
                    var v = 1 - (latNumber / latitudeBands);

                    normalData.push(x);
                    normalData.push(y);
                    normalData.push(z);
                    textureCoordData.push(u);
                    textureCoordData.push(v);
                    vertexPositionData.push(radius * x);
                    vertexPositionData.push(radius * y);
                    vertexPositionData.push(radius * z);
                }
            }

            var indexData = [];
            for (var latNumber = 0; latNumber < latitudeBands; latNumber++) {
                for (var longNumber = 0; longNumber < longitudeBands; longNumber++) {
                    var first = (latNumber * (longitudeBands + 1)) + longNumber;
                    var second = first + longitudeBands + 1;
                    indexData.push(first);
                    indexData.push(second);
                    indexData.push(first + 1);

                    indexData.push(second);
                    indexData.push(second + 1);
                    indexData.push(first + 1);
                }
            }

            moonVertexNormalBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexNormalBuffer);
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(normalData), gl.STATIC_DRAW);
            moonVertexNormalBuffer.itemSize = 3;
            moonVertexNormalBuffer.numItems = normalData.length / 3;

            moonVertexTextureCoordBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexTextureCoordBuffer);
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoordData), gl.STATIC_DRAW);
            moonVertexTextureCoordBuffer.itemSize = 2;
            moonVertexTextureCoordBuffer.numItems = textureCoordData.length / 2;

            moonVertexPositionBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexPositionBuffer);
            gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertexPositionData), gl.STATIC_DRAW);
            moonVertexPositionBuffer.itemSize = 3;
            moonVertexPositionBuffer.numItems = vertexPositionData.length / 3;

            moonVertexIndexBuffer = gl.createBuffer();
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, moonVertexIndexBuffer);
            gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(indexData), gl.STATIC_DRAW);
            moonVertexIndexBuffer.itemSize = 1;
            moonVertexIndexBuffer.numItems = indexData.length;
        }


        function drawScene() {
            gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
            gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

            pMatrix = okMat4Proj(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0);

            var lighting = document.getElementById("lighting").checked;
            gl.uniform1i(shaderProgram.useLightingUniform, lighting);
            if (lighting) {
                gl.uniform3f(
                    shaderProgram.ambientColorUniform,
                    parseFloat(document.getElementById("ambientR").value),
                    parseFloat(document.getElementById("ambientG").value),
                    parseFloat(document.getElementById("ambientB").value)
                );

                var lightingDirection = new okVec3(
                    parseFloat(document.getElementById("lightDirectionX").value),
                    parseFloat(document.getElementById("lightDirectionY").value),
                    parseFloat(document.getElementById("lightDirectionZ").value)
                );

                var adjustedLD = lightingDirection.normalize(false);
                adjustedLD = okVec3MulVal(adjustedLD, -1.0);
                gl.uniform3fv(shaderProgram.lightingDirectionUniform, adjustedLD.toArray());

                gl.uniform3f(
                    shaderProgram.directionalColorUniform,
                    parseFloat(document.getElementById("directionalR").value),
                    parseFloat(document.getElementById("directionalG").value),
                    parseFloat(document.getElementById("directionalB").value)
                );
            }

            mvMatrix = okMat4Trans(0.0, 0.0, -6.0);
            mvMatrix = okMat4Mul(mvMatrix, moonRotationMatrix);

            gl.activeTexture(gl.TEXTURE0);
            gl.bindTexture(gl.TEXTURE_2D, moonTexture);
            gl.uniform1i(shaderProgram.samplerUniform, 0);

            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexPositionBuffer);
            gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, moonVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);

            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexTextureCoordBuffer);
            gl.vertexAttribPointer(shaderProgram.textureCoordAttribute, moonVertexTextureCoordBuffer.itemSize, gl.FLOAT, false, 0, 0);

            gl.bindBuffer(gl.ARRAY_BUFFER, moonVertexNormalBuffer);
            gl.vertexAttribPointer(shaderProgram.vertexNormalAttribute, moonVertexNormalBuffer.itemSize, gl.FLOAT, false, 0, 0);

            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, moonVertexIndexBuffer);
            setMatrixUniforms();
            gl.drawElements(gl.TRIANGLES, moonVertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0);
        }


        function tick() {
            okRequestAnimationFrame(tick);
            drawScene();
        }


        function webGLStart() {
            var canvas = document.getElementById("lesson11-canvas");
            initGL(canvas);
            initShaders();
            initBuffers();
            initTexture();

            gl.clearColor(0.0, 0.0, 0.0, 1.0);
            gl.enable(gl.DEPTH_TEST);

            canvas.onmousedown = handleMouseDown;
            document.onmouseup = handleMouseUp;
            document.onmousemove = handleMouseMove;

            tick();
        }

    </script>


</head>


<body onload="webGLStart();">
    <canvas id="lesson11-canvas" style="border: none;" width="500" height="500"></canvas>
    <br />
    <input type="checkbox" id="lighting" checked />开启光照<br />
    拖拽鼠标，旋转月球。
    <br />

    <h2>平行光：</h2>

    <table style="border: 0; padding: 10px;">
        <tr>
            <td><b>方向：</b>
            <td>X: <input type="text" id="lightDirectionX" value="-1.0" />
            <td>Y: <input type="text" id="lightDirectionY" value="-1.0" />
            <td>Z: <input type="text" id="lightDirectionZ" value="-1.0" />
        </tr>
        <tr>
            <td><b>颜色：</b>
            <td>R: <input type="text" id="directionalR" value="0.8" />
            <td>G: <input type="text" id="directionalG" value="0.8" />
            <td>B: <input type="text" id="directionalB" value="0.8" />
        </tr>
    </table>


    <h2>环境光：</h2>

    <table style="border: 0; padding: 10px;">
        <tr>
            <td><b>颜色</b>
            <td>R: <input type="text" id="ambientR" value="0.2" />
            <td>G: <input type="text" id="ambientG" value="0.2" />
            <td>B: <input type="text" id="ambientB" value="0.2" />
        </tr>
    </table>
    <br />
</body>

</html>
